【摘要】 将巨大芽孢杆菌（Bacillus megaterium）α-淀粉酶基因克隆到短小芽孢杆菌（Bacilluspumilus）中获得表达。将该工程菌发酵液的上清液,经硫酸铵分级盐析和 DEAE-纤维素柱层析,得到纯化的α-淀粉酶。此酶的最适 pH 为6.0;在 pH 5—8之间稳定;最适反应温度为55℃;金属离子 Zn²⁺、Ab²⁺、Cu²⁺、Ag⁺对酶有明显的抑制作用;Ca²⁺、Na⁺、K⁺对酶略有激活作用;3×10^-3mol/L 对氯汞苯甲酸（PCMB）对酶有95%的抑制作用;其免疫性质与枯草芽孢杆菌（Bacillus subtilis）所产生的α-淀粉酶相同。更多还原

【Abstract】 The gene of α-amylase of Bacillus megaterium was cloned and expressed inBacillus pumilus.The purified enzyme was obtained by salting out of（NH₄）₂SO_?and DEAE-cellulose chromotography.The optimum pH of enzyme is 6.0.It is stablebetween pH 5—8.The optimum temperature is 55℃.The activity of enzyme wasinhibited by Zn²⁺,Ab²⁺,Cu²⁺,and a little activated by Ca²⁺,Na⁺、K⁺.When PCMBwas added at the concentration of 3×10^-3mol/L,95% of enzyme activity wasinhibited.The properties of immunology of enzyme are the same as that of α-amylase produced Bacillus subtilis.更多还原